The aging of the population and the epidemic of obesity have led to a rapid increase in the number of older, obese individuals with diabetes. Little is known about the long-term health effects of lifestyle intervention designed to lower weight and increase physical activity in this population. This application, which responds to RFA-DK-12-502, is submitted by one of the 16 clinical centers in the Action for Health in Diabetes (Look AHEAD) Consortium. All 16 clinical sites and the Coordinating Center have submitted parallel applications. This application proposes to continue the Look AHEAD clinical trial as an observational cohort study and to follow participants with new assessments of the health problems of greatest concern in older, obese individuals with type 2 diabetes. We will test whether random assignment to 9-11 years of intensive lifestyle intervention, compared to a control condition of diabetes support and education, results in improvements in 1) physical function, impairment and disability, 2) cognitive function and impairment, 3) diabetes control and microvascular complications, 4) late life depression, and 5) fractures and cancers. Secondary aims are to examine whether subgroup differences observed during the trial (which raised concern about possible unfavorable effects of intensive lifestyle intervention in those with a prio history of cardiovascular disease) endure and whether the excellent weight losses achieved in the intensive lifestyle intervention arm are maintained despite the absence of continued intervention activities. The Continuation will also support ongoing ancillary studies, maintain infrastructure for new ancillary studies, and sustain thorough analyses and publication of the data collected by Look AHEAD. We will continue to follow the Look AHEAD cohort (approximately 4,000 participants) across the 16 clinical sites. Participants entered the trial 9-1 years ago when they were obese or overweight and aged 45-76, and were randomly assigned with equal probability to either an intensive lifestyle intervention that has induced sustained weight loss and increased physical activity or control condition (diabetes support and education). Both arms have had excellent retention. Interventions were discontinued in September, 2012, but follow-up of the cohort continues. This application will fund one additional clinic visit and ongoing telephone-based outcome assessment. This application builds on the remarkable success of the Look AHEAD in inducing and sustaining weight loss and retaining participants. The planned continuation addresses important public health priorities for a rapidly growing and under-studied segment of the US population in a cost-effective manner, leveraging the extensive resources available from Look AHEAD.